A problem with conventional carrying cases is that the beam strength of the top walls of the carrying case when the halves are closed and locked together can be exceeded by heavy loads in the case. This will deform the top walls, making the halves of the case not close smoothly together. This is normally solved by fattening the frame to provide needed top wall strength. The current technology forces this frame fattening to go all around the case, adding weight but over-strengthening the side walls (where there is little stress) and bottom walls (which are usually reinforced with wood).
A second problem with conventional carrying cases is that the locking mechanism generally protrudes into the interior of the carrying case so that it forms an obstruction to the contents being carried in the case. The locking mechanism also passes through an opening cut into the top frame of the case, weakening the frame.